Assuming 35' ....FD 70   contour master.....on a Deere.  I never had any success with the torque wrench MacDon sent with the head. I raise the  head 2-3 ft. off the ground stand in front of the head and eyeball and level the top large tube with the top of the combine feederhouse opening. Then park on a hard level surface. Raise the head about 6-8" off the ground. Make sure the cutter bar is "frowning". Measure the sickle in the center and adjust the outer end on each side 2-3" lower than the center. Get it in the field and set your sickle tilt and down pressure. Get the center running the way you want. If the wings are digging/pushing you tighten the adjustment bolt under the plastic cover/hood. If they are too light or bouncing loosen the adjustment bolt. Generally it only takes turning the adjustment bolt 1 or 2 points on the head of the bolt. Probably know this but just in case